MSR may refer to:
In technology:
- Machine state register, a register used in PowerPC architectures
- Magnetic Stripe Reader, a device used read magnetic stripe cards such as credit cards
- Mars Sample Return Mission, a planned spaceflight mission
- Microsoft Research, the research division of Microsoft
- Microsoft Reserved Partition, a space-management partition on a computer storage device
- Model-specific register, a feature in Intel x86 and x86-64 processor architectures
- Molten salt reactor, an advanced nuclear reactor design
- Medical grade silicone rubber, a type of rubber used in medicine
- medium source rare-earth, a type of light bulb
In entertainment:
- MSR Studios, a New York recording studio
- The Most Serene Republic, a Canadian indie rock band
- Metropolis Street Racer, a Dreamcast racing game
In politics:
- Mouvement social révolutionnaire, a French fascist party
- Movimiento Social Republicano, a neo-fascist political party in Spain
In real-estate/finance:
- Mortgage Servicing Rights, the rights to collect mortgage payments from a borrower for the benefit of the lender
In transportation:
- Michigan Shore Railroad
- Muar State Railway, a railway operating in the Johor Sultanate, British Malaya
- MSR, the ICAO airline code for EgyptAir
- MSR, the IATA airport code for Muş Airport
In science:
- M-sigma relation
- Mining Software Repositories
Other uses:
- Main Supply Route, a military operations supply route
- Milan – San Remo, an annual bicycle race
- Most Serene Republic, a title in the name of various countries
- Mountain Safety Research, a company specializing in outdoor equipment
- MSR, the FIFA and ISO 3166-1 code for Montserrat
- Marine Scientific Research, a term describing activities under UNCLOS
- Modular Sniper Rifle, a sniper rifle produced by Remington Arms
- March, Strathspey and Reel in traditional Scottish bagpiping